TLR-specific activation of whole blood by Gram-negative bacteria. Dose-dependent induction of IL-6 secretion by heat-inactivated Gram-negative bacteria (E coli WT, E coli K12, K pneumoniae, and P aeruginosa) in human whole blood (A). Error bars show ± SEM. Inhibitory effects of anti-TLR4, anti–MD-2, anti-TLR2, and anti-CD14 mAbs on the activation of cells by E coli WT, E coli K12, K pneumoniae, and P aeruginosa. Human whole blood was stimulated with 104 (B) or 106 bacteria (C). The different points per condition represent experiments performed with different healthy blood donors. Because the magnitude of IL-6 production was variable among different donors, results are given as the percentage of inhibition of IL-6 release compared with the condition with the isotype control antibody (corresponding to 100% activation). Horizontal bars represent the mean.
